Golf club head

ABSTRACT

An exemplary golf club head having an increased amount of discretionary mass may be realized by utilizing improved drop angles, an improved average crown height, and/or articulation points. The discretionary mass may be placed low and deep in the club head to improve the location of the center of gravity as well as the inertial properties. A preferred break length may also be utilized to further improve the depth of the center of gravity. In one example, the center of gravity may be positioned to substantially align the sweet spot with the face center of the club head.

RELATED U.S. APPLICATION DATA

Continuation of application Ser. No. 11/717,107, filed on Mar. 13, 2007.

Provisional application No. 60/876,537, filed on Dec. 22, 2006.

The disclosure of each related application is hereby incorporated byreference in its entirety.

BACKGROUND

As technology has progressed, wood-type club heads have evolved from therelatively small persimmon-wood heads to the “oversized” metal clubheads typically found in most modern drivers. Despite the changes insize and materials over the years, modern drivers have failed toovercome certain shortcomings historically associated with traditionalwood-type clubs.

For a golfer to extract maximum performance from a golf club, a clubhead having a mass in the range of 180-250 g is generally provided. Acertain portion of the club head's mass is reserved for components thatprovide structural support. The remaining mass, referred to asdiscretionary mass, may be strategically distributed within the clubhead to improve the head's inertial properties and to orient the CG in adesired location.

In conventional drivers, favorable placement of the CG and enhancementof the moments of inertia (MOI) are limited by the available amount ofdiscretionary mass. Conventional methods of increasing the discretionarymass, e.g. thinning the club head walls and utilizing light-weightmaterials, have yielded relatively small gains in availablediscretionary mass. Conventional drivers have generally failed torealize CG locations and moments of inertia necessary to deliverimproved performance due to limited amounts of attainable discretionarymass.

Generally, golfers have a natural tendency to strike the golf ball aboutthe face center of the club head. The face center, in most drivers, isthe point on the face where maximum energy transfer occurs at ballimpact and is also known as the Coefficient of Restitution (COR) “hotspot”. Although ball impact at the COR “hot spot” yields addedperformance benefits in the form of increased distance, it does notnecessarily produce the most accurate ball flight if the COR “hot spot”is not aligned with the impact point on the club face where no headrotation or gear effect occurs, also known as the “sweet spot”, which isthe orthogonal projection of the club head's center of gravity (CG) ontothe striking face of the head. In currently available club heads, the“sweet spot” is generally located above the COR “hot spot” due to thehigh location of the club head's center of gravity. This unfavorable CGorientation produces a club head where only one of these performancevariables, i.e., distance associated with the COR “hot spot” or accuracyassociated with the “sweet spot”, may be maximized during a single golfshot.

Furthermore, this high “sweet spot” location on the face produces astatistically unfavorable ball contact pattern that results in decreaseddirectional shot consistency. The natural tendency of the golfer tostrike the ball about the face center, on average, results in a largerthan desired distance between the location of the ball at impact and the“sweet spot”. This increased distance exaggerates both the head rotationand gear effect of the club head, causing a loss of carry distance andaccuracy.

Shot accuracy and distance are also affected by the depth of the CGrelative to the club face. In modern drivers, the CG is typicallypositioned near the face. This shallow CG placement prevents the clubhead from dynamically flexing the shaft toward alignment with the CG toloft the head and to close the face at impact with the ball.Additionally, a shallow CG decreases the radius of rotation of the faceon off-center hits, thus decreasing shot accuracy.

SUMMARY

Hence, a need exists for a golf club head that provides an increase indiscretionary mass, lowers the CG in the club head, increases the depthof the CG in the club head, aligns the CG with the center of the face,and improves the MOI of the club head.

Such benefits may be attained by utilizing drop angles, recovery angles,average heights, and break lengths in accordance with the embodiments ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Various implementations will now be described by way of example only,with reference to the following drawings in which:

FIG. 1 is a top plan view of an exemplary golf club in accordance withone aspect of the present invention.

FIG. 1 a is a front elevational view of the golf club head of FIG. 1.

FIG. 1 b is a front perspective view of the golf club head of FIG. 1.

FIG. 2 is a front elevational view of the golf club head of FIG. 1.

FIG. 3 is a front elevational view of the golf club head of FIG. 1.

FIG. 3 a is a front perspective view of the golf club head of FIG. 1.

FIG. 3 b is a top plan view of the golf club head of FIG. 1

FIG. 3 c is a heel side elevational view of the golf club head of FIG.1.

FIG. 4 is a heel side elevational view of the golf club head of FIG. 1.

FIG. 5 is a front elevational view of the golf club head of FIG. 1.

FIG. 6 is a heel side elevational view of the golf club head of FIG. 1.

FIG. 6 a is a heel side elevational view of the golf club head of FIG. 1and a second exemplary golf club head in accordance with another aspectof the present invention.

FIG. 7 is a heel side elevational view of the golf club head of FIG. 1.

FIG. 7 a is a heel side elevational view of the golf club head of FIG. 1and a second exemplary golf club head in accordance with another aspectof the present invention.

FIG. 8 is a front elevational view of the golf club of FIG. 1.

FIG. 9 is a front elevational view of the golf club head of FIG. 1.

FIG. 10 illustrates a non-arcuate junction in accordance with anotheraspect of the present invention.

FIG. 11 a is a heel side elevational view of an exemplary golf club headin accordance with another aspect of the present invention.

FIG. 11 b is a front elevational view of the golf club head of FIG. 11a.

FIG. 11 c is a heel side elevational view of an exemplary golf club headin accordance with another aspect of the present invention.

FIG. 11 d illustrates the non-arcuate junction of FIG. 10.

FIG. 11 e is a heel side elevational view of the golf club head of FIG.11 c.

FIG. 12 is a top plan view of the golf club head of FIG. 1

FIG. 13 is a front elevational view of the golf club head of FIG. 1.

FIG. 14 is a heel side elevational view of the golf club head of FIG. 11a.

FIG. 15 is a heel side elevational view of the golf club head of FIG. 11a.

FIG. 16 is a heel side elevational view of the golf club head of FIG. 11a.

DESCRIPTION

As shown in FIGS. 1 and 1 a, the term “reference position”, as usedherein, denotes a club-head position wherein a hosel 100 has a hoselcenterline 102 oriented in an imaginary vertical plane 104, which isoriented substantially parallel to a strike face 106. As illustrated inFIG. 1 a, the hosel centerline 102 has a lie angle α of substantially60° with respect to a horizontal ground plane 108. In addition, a faceangle θ (FIG. 1) is substantially 0° in relation to an imaginaryvertical plane 110 that passes through a face center 112 and issubstantially parallel to the face 106. The reference position may bedetermined in accordance with the United States Golf Association and R&ARules Limited, “Procedure for Measuring the Club Head Size of WoodClubs,” Revision 1.0, Sections 6.0.1, 6.6, & 6.7 (Nov. 21, 2003). Unlessotherwise indicated, all parameters are specified with the club head 101in the reference position.

The face center 112 (FIGS. 1 & 1 a), as used herein, may be locatedusing the USGA method described in the United States Golf Association's,“Procedure for Measuring the Flexibility of a Golf Club head,” Revision2.0, Section 6.1 (Mar. 25, 2005).

Referring to FIG. 1 b, for purposes of determining moments of inertia(MOI) of a golf club 101 according to the various embodiments of theinvention, a three-dimensional coordinate system having axes x, y, andz, has its origin at the center of gravity CG of the club head 101 withthe club head 101 in the reference position. The Z-axis extends throughthe CG generally parallel to the strike face 106 in a vertical directionrelative to the ground plane 108. The Y-axis extends through the CGsubstantially parallel to the strike face 106 and perpendicular to thez-axis. The X-axis extends through the CG and is perpendicular to the Zand the Y-axes. The relevant MOIs may be determined as follows:

-   -   (1) The MOI about the z-axis (I_(zz)) may be determined using        the method described in United States Golf Association and R&A        Rules Limited, “Procedure for Measuring the Moment of Inertia of        Golf Club heads,” Revision 1.0 (Apr. 12, 2006).    -   (2) The MOI about the y-axis (I_(yy)) is determined using a        measurement instrument, e.g, model number MOI-005-104 made by        Inertia Dynamics, Inc. of Collinsville, Conn., designed for        measuring the moment of inertia of test parts having mass        properties and overall dimensions similar to that of a golf club        head. Referring to FIG. 2, an exemplary measurement instrument        is provided with a horizontal jig plate 120 capable of        accommodating a hosel fixture 118. Proper orientation of the        club head 101 on the hosel fixture 118 is accomplished by        rotating the club head 101, oriented in the reference position,        through 90 degrees so that the toe is pointing upward in the        vertical direction and the CG of the club head 101 is        substantially aligned with the central axis of rotation 114,        which is in the vertical direction, of the measuring instrument.        These measurements are made using methodologies well known to        those skilled in the art.

Referring to FIG. 3, hosel center 122, as used herein, refers to thepoint of intersection between a planar surface 123 and the hoselcenterline 102. The planar surface 123 is characterized by the end ofthe hosel 100.

Referring to FIGS. 3 and 3 a, for purposes of locating the CG of a golfclub head 101 according to the various embodiments of the invention, asecond three dimensional coordinate system, including axes X_(hosel),Y_(hosel), and Z_(hosel), has its origin at the hosel center 122, withthe club head 101 in the reference position. Axis Z_(hosel) extendsthrough the hosel center 122 generally parallel to the strike face 106in a vertical direction relative to the ground plane 108. Axis Y_(hosel)extends through the hosel center 122 substantially parallel to thestrike face 106 and perpendicular to the Z_(hosel) axis. Axis X_(hosel)extends through the hosel center 122 perpendicular to the Z_(hosel) andY_(hosel) axes. The CG of the club head may be located as follows:

-   -   (1) Referring to FIG. 3 b, the CG is located a first horizontal        distance 124 from an imaginary vertical plane 126. The plane 126        is oriented substantially parallel to the face 106 and passes        through the hosel center 122. The distance 124 is the shortest        horizontal distance from plane 126 to the CG;    -   (2) Referring to FIG. 3 b, the CG is located a second horizontal        distance 128 from an imaginary vertical plane 130. The plane 130        is oriented substantially perpendicular to the face 106 and        passes through the hosel center 122. The distance 128 is the        shortest horizontal distance from plane 130 to the CG; and    -   (3) Referring to FIG. 3 c, the CG is located a first vertical        distance 132 from the ground plane 108. The distance 132 is the        shortest vertical distance from the ground plane 108 to the CG.

Referring to FIG. 4, sweet spot 134, as used herein, refers to the pointof intersection between the outer surface of the club face 106 and animaginary line 136 that is substantially perpendicular to the face 106and passes through the CG of the club head 101.

Referring to FIG. 5, center apex 138, as used herein, refers to a pointof intersection between an imaginary vertical plane 140 and the top ofthe strike face 106. The plane 140 is oriented substantiallyperpendicular to the face 106 and passes through the face center 112.

Referring to FIG. 6, break length 142, as used herein, denotes ahorizontal distance, at a height 144 relative to the ground plane 108 ina direction substantially perpendicular to the face 106, between animaginary vertical line 146 and the outer surface of a rear portion 148of the club head 101. The imaginary vertical line 146 extends from thecenter apex 138 to the ground plane 108.

Referring to FIG. 7, the term “average height”, as used herein, denotesan average of a plurality of vertical distances, e.g. F₁ . . . F_(n),between a path 174 and the ground plane 108, in a vertical planecontaining the center apex 138 and a rear-most point 149 of the clubhead 101. Vertical distances F₁ . . . F_(n) may be spaced anywherebetween the apex 138 and the point 149 in horizontal increments havingany desired progression, e.g., equal 5 mm increments.

Referring to FIG. 8, face height 154, as used herein, denotes a verticaldistance, with the club head 101 in the reference position, between afirst plane 156, parallel to the ground plane 108 and passing throughthe highest point 160 of the strike face 106, and a second plane 158,parallel to the ground plane 108 and passing through the lowest point162 of the strike face 106.

Referring to FIG. 9, face length 164, as used herein, refers to ahorizontal distance between a heel end 166 and a toe end 168 along ahorizontal plane 170 passing through the face center 112.

The term “non-arcuate junction”, as used herein, refers to a junction oftwo lines where: an endpoint of an arcuate line meets an endpoint of astraight line (FIGS. 10 a and 10 a′), an endpoint of an arcuate linemeets an endpoint of another arcuate line (FIGS. 10 b and 10 b′), or anendpoint of a straight line meets an endpoint of another straight line(FIG. 10 c).

Referring to FIG. 11 a and 11 b, articulation point 172, as used herein,denotes at least one point along the path 174 where the curvature of thepath 174 changes from concave to convex or vice versa. The path 174 ischaracterized by the intersection of an imaginary vertical plane 140with the top portion of an exemplary club head 143. As shown in FIG. 11b, the imaginary vertical plane 140 is oriented substantiallyperpendicular to the face 106 and passes through the face center 112.Referring back to FIG. 11 a, path 174 is laterally bounded by the centerapex 138 and the rear-most point 149. When determining whether the path174 changes curvature, it is assumed that all non-arcuate junctionsalong the path 174 are arcuate. For example, each non-arcuate junction178 of club head 143, illustrated in FIG. 11 c, is substituted with animaginary junction 180 having an infinitesimally small radius, as shownin FIG. 11 d and 11 e.

Referring to FIG. 12, overall length 182, as used herein, denotes theshortest horizontal distance between a first imaginary vertical plane185, substantially parallel to the strike face 106 and passing throughthe center apex 138, and a second imaginary vertical plane 186 that isparallel to the plane 185 and passes through the rearward most point 149on the club head 101, opposite the strike face 106.

Referring to FIG. 13, overall width 190, as used herein, denotes theshortest horizontal distance between a first imaginary vertical plane192, substantially perpendicular to the strike face 106 and passingthrough the furthest laterally projecting point 196 of the toe 184, anda second imaginary vertical plane 194 that is substantiallyperpendicular to the face 106 and passes through the furthest laterallyprojecting point 198 of the heel 176 having the same height as point196.

Referring to FIG. 14, drop angle β, as used herein, denotes an angleformed by an imaginary vertical line 200 and a line 202 tangent to thepoint of intersection between the line 200 and a path 174. The imaginaryvertical line 200 extends from the path 174 to ground plane 108 at aspecified horizontal distance from the center apex 138, not exceedingthe horizontal distance between apex 138 and point 149. The path 174 ischaracterized by the intersection of an imaginary vertical plane 140with the top portion of the exemplary club head 143. As shown in FIG.14, the imaginary vertical plane 140 is oriented substantiallyperpendicular to the face 106 and passes through the face center 112.Any drop angle β is always measured to the right of the vertical line200 when viewing the club head 143 from a heel side elevational view.

Referring to FIG. 14, recovery angle φ, as used herein, denotes an angleformed by an imaginary vertical line 200 and a line 202 tangent to thepoint of intersection between the line 200 and the path 174. Theimaginary vertical line 200 extends from the path 174 to ground plane108 at a specified horizontal distance from the center apex 138, notexceeding the horizontal distance between apex 138 and point 149. Anyrecovery angle φ is always measured to the left of the vertical line 200when viewing the club head from a heel side elevational view.

The term “volume”, as used herein, may be determined using the methoddescribed in the United States Golf Association and R&A Rules Limited,“Procedure for Measuring the Club Head Size of Wood Clubs,” Revision1.0, Section 5 (Nov. 21, 2003).

Referring to FIGS. 1-16 and the tables below, exemplary club heads inaccordance with the various embodiments of the present invention areshown and described.

In one aspect of the invention, an improved CG location may be achievedby altering the geometry of the crown, e.g., recessing the crown toincrease the available discretionary mass. This increased discretionarymass may be beneficially distributed within the club head to lower theCG. The amount of discretionary mass obtained as a result ofgeometrically altering the crown may be related to the crown's dropangles (FIG. 14), recovery angles (FIG. 14), average height (FIG. 7),and/or number of articulation points (FIG. 11 a). By adapting thesevariables in accordance with the embodiments of the present invention,an increase in discretionary mass may be achieved.

For example, in FIG. 14, an exemplary club head 143 having a crownrecessed toward the ground plane 108 is shown. The crown includes aplurality of drop angles β and recovery angles β, i.e. the angles formedby line 200 and tangent line 202 along the path 174 between the centerapex 138 and point 149. This improved crown orientation increases thediscretionary mass of the club head 143 relative to that of aconventional driver, since less mass is required to form the crown. Theamount of discretionary mass created may vary depending on the drop βand recovery angles φ of the club head. Parameters associated withseveral exemplary embodiments according to the present invention arelisted in Tables 1 and 2, below.

TABLE 1 Horizontal Distance Drop Angle, Drop Angle, from Exemplary ClubExemplary Club Center Apex Head 1 Head 2 2 cm 77.3° 74.3° 3 cm 41.4°47.8° 4 cm 56.7° 58.2° 5 cm 68.4° 63.7° 6 cm 75.3° 68.6° 7 cm 78.9°72.7° 8 cm 81.0° 76.1° 9 cm 82.8° 79.3° 10 cm  80.1° 77.9°

TABLE 2 Horizontal Distance Recovery Angle, Recovery Angle, fromExemplary Exemplary Center Apex Club Head 1 Club Head 2 2 cm 102.7°105.7° 3 cm 138.6° 132.2° 4 cm 123.3° 121.8° 5 cm 111.6° 116.3° 6 cm104.7° 111.4° 7 cm 101.1° 107.3° 8 cm 99.0° 103.9° 9 cm 97.2° 100.7° 10cm  99.9° 102.1°

In accordance with one aspect of the present invention, club head 143may have a drop angle β, preferably between about 35° and about 87°,more preferably between about 40° and about 85°, and most preferablybetween about 50° and 75°, when measured at a horizontal distancebetween about 2 cm and about 11 cm away from the center apex 138. Inanother aspect, the drop angle β, may be between about 40° and about600, more preferably between about 500 and about 600, and mostpreferably between about 41.4° and about 47.80, when measured at ahorizontal distance between about 2 cm and about 4 cm away from thecenter apex 138. Further, club head 143 may also have a recovery angleφ, preferably between about 92° and about 145°, and more preferablybetween about 97° and about 140°, when measured at a horizontal distancebetween about 2 cm and about 11 cm away from the center apex 138. Inanother aspect, the recovery angle φ may be between about 90° and about110°, when measured at a horizontal distance between about 2 cm andabout 4 cm away from the center apex 138. By utilizing drop angles β andrecovery angles φ in the above recited ranges, an increase indiscretionary mass may be obtained. The increased discretionary mass maybe repositioned low and deep in the club head 143 to improve the CGlocation, resulting in improved shot accuracy and distance.

In another embodiment, shown in FIG. 7A, a club head 101 may utilize anaverage height, i.e. an average of a plurality of vertical distances,e.g. F₁ . . . F_(n), between the path 174 and the ground plane 108,adapted to increase the available discretionary mass. For example, byrecessing at least a portion of the crown toward the ground plane 108and thereby lowering the average height relative to that of aconventional driver, less mass is required to form the crown, thusyielding an increase in discretionary mass. Further, vertical distancesF₁ . . . F_(n) may be spaced anywhere between the apex 138 and the point149 in increments having any desired progression, e.g., 5 mm increments,as shown in Table 3. Parameters associated with several exemplaryembodiments according to the present invention are listed in Table 3.

TABLE 3 Height from Horizontal Distance Height from Path to Ground Pathto Ground from Center Apex Plane, Exemplary Club Plane, Exemplary Club[mm] Head 3 [mm] Head 4 [mm] 0 @ center apex 57.1 61.2  5 58.5 62.6 1057.9 62.2 15 57.1 61.3 20 55.2 60.1 25 48.7 54.4 30 42.7 49.5 35 38.645.2 40 35.1 41.9 45 32.6 39.4 50 30.5 36.6 55 28.9 34.4 60 27.7 32.1 6526.4 30.4 70 25.5 28.8 75 24.7 27.3 80 23.8 26.0 85 23.1 24.9 90 22.123.8 95 23.0 100  22.2 Avg. Ht. 37.7 40.4

In accordance with another aspect of the present invention, exemplaryclub head 143 may have an average height, preferably between about 35 mmand about 45 mm, more preferably between about 36 mm and about 41 mm,and most preferably between about 37.7 mm and about 40.4 mm. Theincreased discretionary mass created by utilizing the exemplary averageheights, recited above, may be redistributed in the club head 143 toimprove the mass properties thereof.

In another embodiment of the invention, shown in FIG. 1A, a club head143 including at least one articulation point 172 along a path 174, hasan increased discretionary mass. By utilizing a specified number ofarticulation points 172, a crown shape conducive to a favorable weightdistribution may be achieved. For example, as illustrated in FIG. 11A, arecessed crown 150 may be created by incorporating two articulationpoints 172. The recessed shape of the crown may be adapted to increasethe available discretionary mass by decreasing the mass required to formthe crown. Such weight may be repositioned in club head 143 to increasethe MOI or to place the CG in a more favorable position. This may allowfor a more forgiving club head, resulting in improved shot accuracy anddistance.

Improved placement of the CG may be generally accomplished by depositingthe increased discretionary mass, i.e., the mass obtained by utilizingdrop angles, recovery angles, average heights, and articulation pointsaccording to the embodiments of the present invention, as low and deepas possible in the exemplary club head 143. As shown in FIG. 6,conventional club heads, e.g., club head 101, are limited in theirability to place discretionary weight low and deep due to the geometryof the sole 141. The soles, e.g., sole 141, of conventional club headsare generally elevated with respect to the ground plane 108, whichprevents discretionary mass from being deposited as close as possible tothe ground plane 108. Thus, in another aspect of the invention, shown inFIG. 6A, a sole 139, having the break length 142 near the ground plane108, may be utilized to position the increased discretionary mass as lowand deep as possible in the exemplary club head 143. Parametersassociated with an exemplary embodiment according to the presentinvention are listed in Table 4.

TABLE 4 Vertical distance up from Break Length, Exemplary Club GP [mm]Head 5 [mm.] 1 53.6 2 69.9 3 81.3 4 90.7 5 99.1 6 101.1 7 102.1 8 102.69 103.1 10 103.4 11 103.6 12 103.6 13 103.9 14 103.9 15 103.9 16 103.917 103.9 18 103.9 19 103.6 20 103.1 21 102.6 22 101.3 23 98.3

In some embodiments of the present invention, club head 143 may have abreak length 142 between about 50 mm and about 110 mm at the verticalheight 144 between about 1 mm and about 15 mm relative to the groundplane 108. The break length 142, may be, preferably, between about 90 mmand about 110 mm, more preferably between about 96.5 mm and about 140mm, and most preferably, between about 100 mm and about 130 mm at avertical height 144 between about 5 mm and about 10 mm relative to theground plane 108. The break length 142 in accordance with theembodiments of the present invention, allows discretionary mass to beplaced low and deep within the club head 143, yielding an improved CGlocation.

Referring to FIGS. 4 and 15, in another aspect of the present invention,the increased discretionary mass may be positioned low in the club head143, e.g., by utilizing the break length 142 so that the sweet spot 134is substantially aligned with the COR “hot spot”, i.e., the face center112. By lowering the CG and aligning the sweet spot 134 with the COR“hot spot” 112, the benefits of these performance variables, i.e., theincreased shot distance associated with the COR “hot spot” 112 andincreased accuracy associated with the “sweet spot” 134, may be realizedsimultaneously. Thus, the club head 143, providing improved shotaccuracy and distance, may be achieved.

Referring again to FIG. 15, another aspect of the present invention isto position the discretionary mass deep within the club head 143, e.g.,by utilizing the break length 142, to increase the CG depth, i.e., thehorizontal distance from the CG to the strike face 106. The exemplaryclub head 143, having a CG with such an increased depth, dynamicallyflexes the shaft toward alignment with the CG to loft the head 143 andto close the face 106 at impact with the ball. Additionally, the deep CGof club head 143 may increase the radius of rotation of the face 106 onoff-center hits, thus improving shot accuracy.

CG location coordinates associated with several exemplary embodimentsaccording to the present invention are listed in Table 5.

TABLE 5 Exemplary Exemplary Exemplary CG Location Club Head 6 Club Head7 Club Head 8 First Horizontal 19.6 mm 31.0 mm 28.2 mm Distance SecondHorizontal 62.2 mm 63.0 mm 70.6 mm Distance First Vertical 26.2 mm 27.4mm 28.7 mm Distance

Referring to FIGS. 3 b and 3 c as well as Table 5, in some embodimentsof the present invention, first horizontal distance 124 may preferablybe between about 12 mm and about 38 mm, more preferably between about 15mm and about 36 mm, and most preferably between about 25 mm and about 35mm. Second horizontal distance 128 may preferably be between about 55 mmand about 78 mm, more preferably between about 58 mm and about 74 mm,and most preferably between about 58 mm and about 66 mm. First verticaldistance 132 may preferably be between about 20 mm and about 33 mm, morepreferably between about 20 mm and about 28 mm, more preferably betweenabout 22 mm and about 30 mm, and most preferably between about 25 mm andabout 30 mm.

In addition to improving the CG location, some discretionary weight maybe repositioned in the face to make the face taller and wider. A largeface, for example, may instill increased confidence in a golfer. Suchimproved confidence may result in increased club head speed, which mayimprove overall ball carry. Furthermore, some discretionary weight mayalso be strategically positioned around the rear portion of the shell.This may increase the MOI about the vertical (I_(zz)) and horizontal(I_(yy)) axes and may ultimately improve performance on off center hitsby reducing slice/hook tendencies.

Table 6 lists moment of inertia, face height, and face lengthmeasurements for several exemplary embodiments according to the presentinvention:

TABLE 6 Exemplary Exemplary Exemplary Club Head 7 Club Head 8Measurement Club Head 6 (CH6) (CH7) (CH8) I_(yy) 2486 g · cm² 3149 g ·cm² 2866 g · cm² I_(zz) 3878 g · cm² 4538 g · cm² 4394 g · cm² FaceHeight 49.3 mm 52.6 mm 54.6 mm Face Length 101.3 mm 104.9 mm 105.7 mm

Referring to FIG. 1 b and Table 6, in some embodiments of the presentinvention, I_(yy) may preferably be at least about 2300 g·cm², morepreferably be between about 2300 g·cm² and about 3300 g·cm², and mostpreferably be between about 2700 g·cm² and about 3300 g·cm². I_(zz) maypreferably be at least about 3700 g·cm², more preferably be betweenabout 3700 g·cm² and about 4700 g·cm², or most preferably be betweenabout 3800 g·cm² and about 4600 g·cm².

Referring to FIGS. 8 and 9, as well as Table 6, in some embodiments ofthe present invention, the face height 154 may preferably be betweenabout 43 mm and about 61 mm, more preferably between about 45 mm andabout 58 mm, and most preferably between about 48 mm and about 58 mm.The face length 164 may preferably be between about 94 mm and about 115mm, more preferably between about 96 mm and about 112 mm, and mostpreferably between about 98 mm and about 110 mm.

Referring to FIG. 16, an exemplary golf club 208, shown with thewood-type club head 143, may include a shaft 206, connected to a head143 by a hosel 100. Head 143, may include a hollow shell formed by thestrike face 106 and a body portion 204. The hollow shell may have theheel portion 176, the toe portion 184, the crown portion 150, and thesole portion 141.

Further, head 143 may be formed from a wide variety of materials,including metals, polymers, ceramics, composites, and wood. Forinstance, the club heads of the present invention may be made fromstainless steel, titanium, or graphite fiber-reinforced epoxy, as wellas persimmon or laminated maple. In one exemplary embodiment, club head143 is formed, at least in part, of fiber-reinforced orfiberglass-reinforced plastic (FRP), otherwise known as reinforcedthermoset plastic (RTP), reinforced thermoset resin (RTR), andglass-reinforced plastic (GRP).

In one preferred exemplary embodiment, the body portion 204 may beprovided with the face 106 formed of SP700 Beta Titanium—an alpha/betagrade alloy of 4.5-3-2-2 Titanium (Ti-4.5% Al-3% V-2% Mo-2% Fe). Inalternate embodiments, portions of head 143 may be formed of othertitanium alloys including a forging of a high strength titanium alloysuch as 10-2-3 (Ti-10% V-2% Fe-3% Al) or 15-3-3-3 (Ti-15% V-3% Cr-3%Sn-3% Al), a casting of a 6-4 alloy (Ti-6% Al-4% V), or other titaniumalloys such as 3-2.5 Titanium (Ti-3% Al-2.5% V) or 15-5-3 Titanium(Ti-15% Mo-5% Zr-3% Al). In other embodiments, other forging and castingalloys may be used including stainless steel and aluminum.

In some embodiments, the volume of the club head may be at least about200 cm³, more preferably between about 300 cm³ and about 500 cm³; andmost preferably between about 310 cm³ and about 400 cm³.

A variety of club shafts are contemplated for use with the variousembodiments of the present invention, including the shafts 206 that, forexample, may be made from chrome-plated steel, stainless steel,aluminum, carbon or graphite fiber-reinforced epoxy, boronfiber-reinforced epoxy, or titanium. The shaft 206 may be provided witha grip, for example, formed from molded synthetic rubber or wrappedleather.

In addition, the present invention may relate to a golf club and a setof golf clubs having the inventive golf club heads described herein. Forexample, the set may be a set of wood-type golf clubs which may havemetallic golf club heads.

While various aspects of the present invention are described above, itshould be understood that the various features of the invention may beused singly or in any combination thereof. Therefore, this invention isnot to be limited to only the specifically preferred embodimentsdepicted herein. Further, it should be understood that variations andmodifications within the spirit and scope of the invention may occur tothose skilled in the art to which the invention pertains. Accordingly,all expedient modifications readily attainable by one versed in the artfrom the disclosure set forth herein that are within the scope andspirit of the present invention are to be included as furtherembodiments of the present invention. The scope of the present inventionis accordingly defined as set forth in the appended claims.

1. A golf club head having a reference position, the golf club headcomprising: a strike face comprising a center apex; a body portion,associated with the strike face, comprising a top portion and arear-most point; an imaginary vertical plane substantially perpendicularto the strike face and containing the center apex and the rear-mostpoint; and a path between the center apex and the rear-most point, thepath characterized by an intersection between the imaginary verticalplane and the top portion of the body, wherein, the path comprises anaverage height between about 35 mm and about 45 mm with the club head inthe reference position.
 2. The golf club head of claim 1, wherein thepath comprises at least two articulation points.
 3. The golf club headof claim 1, further comprising: a hosel, associated with the bodyportion, having a hosel center; and a center of gravity located a firsthorizontal distance, between about 25 mm and about 35 mm, from animaginary vertical plane oriented substantially parallel to the strikeface and passing through the hosel center.
 4. The golf club head ofclaim 1, wherein the strike face has a face height between about 45 mmand about 58 mm, and a face width between about 94 mm and about 115 mm.5. The golf club head of claim 1, further comprising: an imaginarycoordinate system having an origin located at a center of gravity of thegolf club head, the coordinate system having an x-axis, a y-axis, and az-axis, wherein the head has an MOI of at least 3700 g·cm² about thez-axis.
 6. The golf club head of claim 1, further comprising: animaginary coordinate system having an origin located at a center ofgravity of the golf club head, the coordinate system having an x-axis, ay-axis, and a z-axis, wherein the head has an MOI of at least 2300 g·cm²about the y-axis.
 7. The golf club head of claim 1, wherein the head hasa volume of at least 200 cm³.
 8. The golf club head of claim 1, whereinthe strike face further comprises a face center, and a sweet spotsubstantially coincident with the face center.
 9. The golf club head ofclaim 1, further comprising: an imaginary vertical line extending fromthe center apex to a ground plane, wherein the body portion has a breaklength, between about 90 mm and about 110 mm, measured with respect tothe imaginary vertical line at a vertical height between about 5 mm andabout 10 mm from the ground plane.
 10. A golf club head having areference position, the golf club head comprising: a strike facecomprising a center apex; a first imaginary vertical line extending fromthe center apex to a ground plane, and a body portion, associated withthe strike face, the body portion having a break length, between about96.5 mm and about 140 mm, measured with respect to the first imaginaryvertical line at a vertical height between about 5 mm and about 10 mmfrom the ground plane, with the club head in the reference position. 11.The golf club head of claim 10, further comprising: a hosel, associatedwith the body portion, having a hosel center; and a center of gravitylocated a first horizontal distance, between about 25 mm and about 35mm, from an imaginary vertical plane oriented substantially parallel tothe strike face and passing through the hosel center.
 12. The golf clubhead of claim 10, wherein the strike face has a face height betweenabout 45 mm and about 58 mm, and a face width between about 94 mm andabout 115 mm.
 13. The golf club head of claim 10, further comprising: animaginary coordinate system having an origin located at a center ofgravity of the golf club head, the coordinate system having an x-axis, ay-axis, and a z-axis, wherein the head has an MOI of at least 3700 g·cm²about the z-axis.
 14. The golf club head of claim 10, furthercomprising: an imaginary coordinate system having an origin located at acenter of gravity of the golf club head, the coordinate system having anx-axis, a y-axis, and a z-axis, wherein the head has an MOI of at least2300 g·cm² about the y-axis.
 15. The golf club head of claim 10, whereinthe head has a volume of at least 200 cm³.
 16. The golf club head ofclaim 10, wherein the strike face further comprises a face center, and asweet spot substantially coincident with the face center.
 17. The golfclub head of claim 10, wherein the break length is between about 90 mmand about 110 mm at a vertical height between about 5 mm and about 10 mmfrom the ground plane.
 18. A golf club head having a reference position,the golf club head comprising: a strike face; a body portion associatedwith the strike face; a hosel, associated with the body portion, havinga hosel center; and a center of gravity located a first horizontaldistance, between about 25 mm and about 35 mm, from an imaginaryvertical plane oriented substantially parallel to the strike face andpassing through the hosel center, with the club head in the referenceposition, and wherein the center of gravity is located a first verticaldistance, between about 20 mm and about 28 mm, from a ground plane, withthe club head in the reference position.
 19. The golf club head of claim18, wherein the strike face has a face height between about 45 mm andabout 58 mm, and a face width between about 94 mm and about 115 mm. 20.The golf club head of claim 18, further comprising: an imaginarycoordinate system having an origin located at a center of gravity of thegolf club head, the coordinate system having an x-axis, a y-axis, and az-axis, wherein the head has an MOI of at least 3700 g·cm² about thez-axis.
 21. The golf club head of claim 18, further comprising: animaginary coordinate system having an origin located at a center ofgravity of the golf club head, the coordinate system having an x-axis, ay-axis, and a z-axis, wherein the head has an MOI of at least 2300 g·cm²about the y-axis.
 22. The golf club head of claim 18, wherein the headhas a volume of at least 200 cm³.
 23. The golf club head of claim 18,wherein the strike face further comprises a face center, and a sweetspot substantially coincident with the face center.
 24. A golf club headcomprising: a strike face having a face center and a sweet spotsubstantially coincident with the face center; a body portion associatedwith the strike face; and an imaginary coordinate system having anorigin located at a center of gravity of the golf club head, thecoordinate system having an x-axis, a y-axis, and a z-axis, wherein thehead has an MOI of at least 3700 g cm² about the z-axis.
 25. The golfclub head of claim 24, further comprising: a top portion and a rear-mostpoint on the body portion; an imaginary vertical plane substantiallyperpendicular to the strike face and containing the center apex and therear-most point; and a path between the center apex and the rear-mostpoint, the path characterized by an intersection between the imaginaryvertical plane and the top portion of the body, wherein the path has anaverage height between about 35 mm and about 45 mm.
 26. The golf clubhead of claim 25, wherein the path comprises at least two articulationpoints.
 27. The golf club head of claim 24, further comprising: a hosel,associated with the body portion, having a hosel center; and a center ofgravity located a first horizontal distance, between about 25 mm andabout 35 mm, from an imaginary vertical plane oriented substantiallyparallel to the strike face and passing through the hosel center. 28.The golf club head of claim 24, wherein the strike face has a faceheight between about 45 mm and about 58 mm, and a face width betweenabout 94 mm and about 115 mm.
 29. The golf club head of claim 24,further comprising: an imaginary coordinate system having an originlocated at a center of gravity of the golf club head, the coordinatesystem having an x-axis, a y-axis, and a z-axis, wherein the head has anMOI of at least 2300 g·cm² about the y-axis.
 30. The golf club head ofclaim 24, wherein the head has a volume of at least 200 cm³.
 31. Thegolf club head of claim 24, further comprising: an imaginary verticalline extending from a center apex to a ground plane, wherein the bodyportion has a break length, between about 90 mm and about 110 mm,measured with respect to the imaginary vertical line at a verticalheight between about 5 mm and about 10 mm from a ground plane, with theclub head in the reference position.
 32. A golf club head comprising: astrike face comprising a face center and a sweet spot substantiallycoincident with the face center; a body portion associated with thestrike face; and an imaginary coordinate system having an origin locatedat a center of gravity of the golf club head, the coordinate systemhaving an x-axis, a y-axis, and a z-axis, wherein the head has an MOI ofat least 2300 g·cm² about the y-axis.
 33. The golf club head of claim32, further comprising: a hosel, associated with the body portion,having a hosel center; and a center of gravity located a firsthorizontal distance, between about 25 mm and about 35 mm, from animaginary vertical plane oriented substantially parallel to the strikeface and passing through the hosel center.
 34. The golf club head ofclaim 32, wherein the strike face has a face height between about 45 mmand about 58 mm, and a face width between about 94 mm and about 115 mm.35. The golf club head of claim 32, further comprising: an imaginarycoordinate system having an origin located at a center of gravity of thegolf club head, the coordinate system having an x-axis, a y-axis, and az-axis, wherein the head has an MOI of at least 3700 g·cm² about thez-axis.
 36. The golf club head of claim 32, wherein the head has avolume of at least 200 cm³.
 37. The golf club head of claim 32, furthercomprising: an imaginary vertical line extending from a center apex to aground plane, wherein the body portion has a break length, between about90 mm and about 110 mm, measured with respect to the imaginary verticalline at a vertical height between about 5 mm and about 10 mm from theground plane, with the club head in the reference position.